CA-125 Test: What You Need to Know

 Since this is a subject of panic that comes up many, many times in the support group, I decided that my blog needed to address this particular topic. Whether or not I can actually make an ambitious database, I do want to at least play a part in making more of this information readily available, especially when doctors aren’t always willing to disclose it or overlook the importance of explaining some of the blood panels they order when women are diagnosed with fibroids.

Among them, the CA-125. When you look it up and see Cancer Antigen are what the CA stands for, even the most laidback person gets hit with anxiety. The thing is, in medical discoveries they often attach a label apropos to the reason they are studying the properties of compositions and functions to begin with, not how it may be used to indicate other things. So that’s the first issue with researching what it is.

The secondary problem is that it IS primarily stated to be used as ‘an indicator for the effectiveness of treatment for ovarian cancer’. So the c-word comes up once again but the primary indicator isn’t actually what doctors are looking for. Why? Because blood tests and scans cannot confirm cancer; this is something you will find in research many times over but it’s easy to forget when the c-word gets thrown about. So what are they looking for? Well, the next useful application is confirming the presence of fibroids, endometriosis and even just menstruation. Under 25 is the ‘normal range’ but when you look into the information, you will find the statement that some women have naturally elevated levels.

Third, it doesn’t state which thresholds indicate which conditions. Because it can’t. Biopsy is still the ONLY way to 100% confirm cancer and cannot be used to diagnose ANYTHING. So why do they use it at all? Number one, getting your baseline. In the event that cancer is found (again, SUPER slim but you do want your doctor to take all precautions, right?) they have a number to frame how these antigen levels are affected by treatment. And this is where the ‘primary’ indication comes in; it IS actually the best way to tell if treatments are effective because it is the ONLY panel where the changes can show significance in the progression or remission of ovarian cancer. HOWEVER, the reason why your doctor wants it prior to surgery is to determine whether an oncological surgeon should do the surgery or your regular OBGYN. Oncologists are specifically trained to know how to remove any cancerous cells most effectively to prevent it from becoming aggressive and ideally remove every bit of suspicious tissue. A gynecological surgeon does not to remove tissue this particularly because most remnants of a mass can be reabsorbed into the body without consequence.

So what are the thresholds? Beyond the 'safe zone' of under 25, largely undefined. Two things will factor into whether oncology needs to be involved: the edges of the mass in the scan (fuzzy edges can be concerning but again, not confirmation of cancer) and grossly elevated CA-125 levels. The jury is out on what constitutes but this number tends to be in the 4,000-10,000 range though some doctors will flinch for anything close to 1,000. 

If no suspicion of cancer is confirmed on biopsy, they will likely once again test the antigen levels; a significant drop, especially closer to the normal range, will tell them that the fibroids were the cause and you're in the clear. Highly elevated levels will tell them that more scans and tests, possibly more surgeries would be needed. That scenario is even less likely; cysts, polyps and troublesome fibroids are typically easily visualized. The exception would be if the doctor misinterpreted the scans and the positioning of the mass and it was not where expected once the area is reached. This tends to be a possibility with laparoscopic or vaginal hysteroscopy where it is located inside/outside when the other was suspected. This can happen when the scan doesn’t capture all angles well or is not as thorough as it should have been. Sometimes contrast or additional rounds are needed to correct this, but it can also be human error.

To summarize, CA-125 has many applications throughout treatment of fibroids but it is likely being used to determine precautions for surgery and having a baseline to see how treatment or surgery affects it. It is NOT an indicator of cancer, just a baseline reading.

I hope this was helpful and that you can help spread the word to those startled by this and many other quite impactful pieces of information. The problem and symptoms often cause high anxiety to begin with so any way we can make this process less stressful for other women is priceless!